Features of English Idioms

Phraseological units or idioms are characterized by a double sense: the current meanings of constituent words build up a certain picture, but the actual meaning of the whole unit has little or nothing to do with that picture in itself creating an entirely new image. Such examples are:

To paint the town red

If we take the constituent words separately we'll see that this idiom's meaning is, ‘To paint all the buildings of the town red’. But as a whole it means, ‘To go out and party; have a good time.’

Grass is always greener on the other side.
This idiom does not mean grass which one side is green and the other one has lost its colour. Its entire meaning is 'a place or situation that is far away or different seems better than one's present situation'. Thus, these ready-made constructions display semantic integrity; functional, semantic, and lexical stability. We can’t replace the members of the word groups at our will or change them without having to the overall meaning.

They are characterized by certain ‘setness’, as well as fully or partially transferred meanings or idiomaticity (Arnold I. V.). Many of them carry out an emotive function and are stylistically significant. So, the idiomatic expressions, though lexically complex are semantically simplex, functioning as single semantic entities, not to mention the structural and functional stability stylistic reference. Another example, which proves that the structural organization of phraseological units resist interruption and ordering, is:

To talk until one is blue in the face.

It is obvious from this idiom that it is lexically complex, semantically simplex and has structural and functional stability. Its meaning is, ‘to talk until one is exhausted’ and if we try to change the word order of this phrase or just add new words, it will lose its meaning or attain a new meaning. Another such example is:

White elephant.

In this idiom the word ‘elephant’ is not used in its direct meaning, here it means 'a useless possession' but if we replace e.g. ‘horse’ instead of ‘elephant’, the whole meaning of the idiom will lose its color and required image.